As is known in the art, adaptive optics is an essential component for optical aberration correction in applications where optical energy is transmitted through an aberration producing medium, such as the atmosphere. Thus, while the energy leaving a laser is typically desired to have a planar wavefront (where all wavelets in the energy are in-phase) to produce maximum power on a distant target in the theoretical absence of medium produced aberrations (FIG. 1A), medium produced aberrations produce different phase delays to the wavelets thereby distorting the wavefront resulting in less than maximum power being produced at the target (FIG. 1B). Adaptive optics is sometimes used to correct for these undesirable atmospheric aberrations producing effects. Many current methods are mechanical in nature (deformable mirrors, MEMs) and often cannot handle the power levels envisioned for high energy laser applications.
As is also known in the art, an adaptive optic liquid crystal device is useful as an optic component in many applications. One such adaptive optic is shown in FIG. 2 to include liquid crystal molecules disposed between a pair of alignment layers (which induce uniform planar alignment of the liquid crystal near the surfaces of the pair of alignment layers), the pair of alignment layers being disposed between a pair of electrode layers; here an array (FIG. 2A) of Indium Tin Oxide (ITO) optically transparent electrodes and a ITO ground plane conductor, which, are disposed between on a substrate and a superstrate, respectively, as shown in FIG. 2. The input beam of light from the laser passes successively through a transparent substrate (having electronics for producing control signals for the electrodes), an array of transparent electrodes, liquid crystal molecules, a transparent ground plane conductor, and a superstate to produce an output beam, as indicated. The each one of the electrodes in the array is associated with a corresponding pixel, or wavelet, of the output beam. Each one of the electrodes is driven by an AC voltage. The voltages produce electric fields (e) through the liquid crystal molecules in a direction perpendicular to the surface of the array of electrodes and the ground plane conductor to change the orientation of the liquid crystal molecules in the corresponding wavelet. The relative phases of the wavelets are adjusted in accordance with the relative magnitude of the voltages fed to the electrodes and thus the adaptive optic may be used to modify the shape of the wavefront of the laser beam to correct for atmospheric aberrations. For example, while many techniques have been used and suggested to determine the requisite phase shifts controlled by the electrodes, one technique measures the power at the target and varies the phase shift until maximum power is received at the target. Thus, in effect the wavefront produced by the adaptive optic is the conjugate of the phase shifts produced by the atmospheric aberrations. Unfortunately, the electrodes are not 100 percent transmissive and absorb some light energy. For example, common electrode material ITO absorbs close to 1% power. Further, heat generated within the ground plane conductor must be removed; and in the system of FIG. 2, such heat must be removed from the outer edges of the ground conductor.